At present, there are a number of earthquake forecast schemes. Among the schemes, the VAN scheme developed in Greece is world widely known. This scheme forecasts the occurrence of an earthquake through observation of a potential difference, that is, a telluric electrical current, between two locations. In Japan, a plurality of organizations have been engaged in empirical studies and research regarding this scheme. However, it is unknown as of November 2001 as to whether the scheme is ready for practical use. According many opinions, it seems that the scheme is not yet usable at least in Japan where many types of noise, such as that of trains.
In general, it can be said that regrettably no “definitive earthquake forecasts” are possible in the world.
In the field of earthquake forecast, example cases have been reported in which, for example, electromagnetic waves and atmospheric ion densities, are observed as a precursory phenomenon. In an academic view, the correlation between geophysical data and earthquakes needs to be reported; practically, however, the research is in a state where it is difficult to verify the correlation.
Although it is a matter not related to earthquakes, an area meteorological observation system called AMeDAS is popularly known in Japan. AMeDAS stands for Automated Meteorological Data Acquisition System, which is abbreviated to as AMeDAS, hereinbelow. At present in Japan, with AMeDAS, which is the area meteorological observation system, weather is observed for, for example, the rainfall rate automatically, at unmanned weather observation stations installed in 1,300 spots (at spacings at about 17 km). At about 840 (at spacings at about 21 km) of the 1,300 spots, rainfall rates, wind direction/wind speed, temperature, sunshine duration, and the like are observed. In addition, snow depths are observed at 200 spots in heavy snowfall regions.
The observation data are collected in an area meteorological observation center in Tokyo, and are subjected to an automatic edit processing. Thereafter, the data are delivered to individual regional weather stations. In addition, in AMeDAS, the edited data are displayed at the final stage over a two-dimensional map, which is well known in weather forecasts and the like.
Strictly speaking, since AMeDAS serves only as an area meteorological observation system, it does not cover the part of performing visual indication on a map. Generally, however, AMeDAS seems to be known as a “precipitation indication system”.
Returning now to the matter of earthquake forecast, in the present situation, none have yet been found that display a “location where an earthquake would occur” on a two-dimensional map. That is, while the display of meteorological data is already implemented through AMeDAS, none that are equivalent to AMeDAS have yet been found to handle earthquake forecast data.
Precursors enabling earthquake forecast include, for example, an electromagnetic phenomenon, a meteorological phenomenon, and an increasing phenomenon in atmospheric ion density. However, even if the individual phenomena are represented as instantaneous values, the representation does not indicate a “location where an earthquake would occur”.
The above will be described hereinbelow with reference to the atmospheric temperature by way of example of meteorological factors. Increases in earth surface temperature before the occurrence of a very great earthquake are observed in, for example, Japan, Russia, Mainland China, and the U.S.A. Increase in earth surface temperature is thought to affect even the atmospheric temperature, which is the temperature of a portion 1.5 m above the earth surface. However, an earthquake-occurrence location cannot easily be explicitly indicated in accordance with the atmospheric temperature. That is, the “location where an earthquake would occur” cannot be indicated unless information processing is performed for atmospheric temperature values that are developed as “raw data”.
Thus, no technical concepts have arisen from the beginning for implementing display of a location explicitly indicative of the “location where an earthquake would occur”. Even if such concepts arose, no disambiguation has been made as to what information processing would implement the display. Thus, while a system for displaying the “location where an earthquake would occur” has been demanded, none has yet been realized.